“Income segregation” refers to the extent to which high- and low-income families within a metropolitan area live near one another.

“The growth in income segregation over the last four decades is quite substantial, particularly given that racial segregation has declined slowly during the same time period,.” said Sean Reardon, a professor at Stanford University, who co-authored the study with Kendra Bischoff, a Stanford postdoctoral fellow.

“Increasing income segregation means not only that low-income families are increasingly concentrated in poor neighborhoods, but also that high-income families are increasingly isolated from middle- and low-income families,” Reardon said. “This isolation of the rich may make it less likely that they support policies and public investments that are beneficial to everyone, such as schools, parks, and public services.”

In 1970, only 15 percent of families were in affluent neighborhoods (where median incomes were greater than 150 percent of the metro area’s median income) or poor neighborhoods (where median incomes were less than 67 percent). By 2007, 31 percent of families lived in such neighborhoods.

From 1970 to 2007, income segregation among both black and Hispanic families increased more than four times faster than it did among white families from 2000 to 2007. Income segregation among black and Hispanic families is now almost twice as high as among white families.

Three of the four most segregated metropolitan areas are in the New York City region: Bridgeport-Stamford-Norwalk, Conn.; New York-Wayne-White Plains, N.Y.-N.J.; and Newark-Union, N.J. An additional three of the top 10 are in Texas: Dallas-Plano-Irving; Houston-Baytown-Sugar Land; and Austin-Round Rock.

Only 13 of the 117 large and moderate-sized metropolitan areas showed decreased family income segregation from 2000 to 2007. Most were in the South, and a number of them were very large metropolitan areas such as Atlanta, Washington, D.C., and Phoenix. The New Orleans metro area experienced the third-largest decline, most likely due to the dramatic population redistribution after Hurricane Katrina.

Philadelphia saw the greatest increase in income segregation from 1970-2007, leaping from 43rd in 1970 to 3rd in 2007. In 1970, only 16 percent of Philadelphia families lived in poor or affluent neighborhoods; in 2007, 43 percent of families lived in such neighborhoods.

US2010 is a program of research on changes in American society in the recent past, with the expertise of a nationwide team of scholars who were brought together for this purpose. For more information, see the project webpage: www.s4.brown.edu/us2010.

Supported by the Russell Sage Foundation and Brown University, US2010 project will culminate with a 14-chapter book published by Russell Sage, which has a 50-year tradition of publishing respected, authoritative, census-based research.